When manufacturing, for example, a bladed disk (blisk), which is an integrated structure of a disk and blades, serving as a rotor of a compressor or turbine of a gas turbine engine, friction joining is sometimes used because the friction joining is able to reduce a material cost and shorten a processing time compared with machining. General friction joining will briefly be explained.
Joining surfaces of a pair of metal parts to be integrated into a joined structure such as a bladed disk are faced to each other. In this state, one of the metal parts is moved relative to the other so that the joining surfaces of the pair of metal parts come into contact with each other. In the state that the joining surfaces of the pair of metal parts face each other and are in contact with each other, one of the metal parts is reciprocated relative to the other in a direction orthogonal to the facing direction. At the same time, one of the metal parts is pressed to the other until a movement (displacement) of the pair of metal parts reaches a target movement (displacement). This discharges burrs including oxides and stains from the joining surfaces of the pair of metal parts and softens with frictional heat the joining surfaces of the pair of metal parts, thereby joining them together.
Related arts concerning the present invention are, for example, Japanese Unexamined Patent Application Publications No. 2009-297788 (Patent Literature 1), No. 2005-199355 (Patent Literature 2), and Japanese Patent Publication No. 3072239 (Patent Literature 3).